"It is later, probably when he is sexually frustrated, he'll generally say as a whole how lacking our S life has ALWAYS been."
Oh good grief. Not one of those "always"-type comments. Those are so frustrating. You ALWAYS do this or you NEVER do that, when it is clear those statements are not true. I think you should ask him point blank, what is it about our SL that has "always" been bad? It is obviously not the individual encounters because you say X & Y afterwards.
"Then I'm afraid to ask him things because I just don't want to find out how inept I am at Sex or anything physical."
Well, if he is crass enough to say something stupid like "you are inept" then you have a whole new problem dealing with respect. You should respond by calmly stating that if you have a problem with my "technique" then why don't you bring it up during or immediately after and BE SPECIFIC.
If you feel like you don't have the skills that you think you should have, then maybe some of the ladies here can suggest some reading for you. I'm sure you could become skilled in no time.
Chrome
"Recollect me darlin, raise me to your lips, two undernourished egos, four rotating hips"